KnowraPerfect numberLinked fromLinked fromThe 7 pages that link to Perfect number, each with the reason it gives.All 7Broader topic 3Related 3Narrower topic 1Divisor functionRelated: A perfect number satisfies σ(n)=2n.Even numberRelated: Every known even perfect number has a form tied to a Mersenne prime.Catalan–Mersenne conjectureRelated: Every even perfect number is associated with a Mersenne prime, a central neighboring topic.